BiCMOS technology combines bipolar technology and CMOS technology. CMOS technology offers lower power dissipation, smaller noise margins, and higher packing density. Bipolar technology provides high switching and input/output I/O speed and good noise performance. BiCMOS technology accomplishes improved speed over CMOS and lower power dissipation as compared to bipolar technology.
If existing CMOS implants are used for bipolar devices, then the bipolar gain or some other parameter or feature is generally compromised. Accordingly, a drawback of adding bipolar transistors in a CMOS process flow is extra mask levels and implants needed to provide good performance for both the bipolar devices and CMOS devices. The extra mask levels results in a process cost increase and added defect density as compared to conventional CMOS technology.